The most effective conventional gaseous fire extinguishing systems available comprise the HALON-class of flame retardants and fire extinguishers, which enjoy wide usage and acceptance within the civilian and military communities. For example, HALON 104 containing carbon tetrachloride (CCl.sub.4) is conventionally used to fight electrical fires. The most effective and widely used fire extinguishing agents contain bromine compounds which thermally decompose in a fire or flame to produce the bromide anion (Br.sup.-) which disrupts the chain reactions involved in the burning process.
However, the HALON-class of fire extinguishers are environmentally unacceptable and are believed to cause depletion of the upper atmosphere ozone layer. Accordingly, the manufacture of HALONS was banned on Dec. 31, 1994 and the manufacture of chlorofluorocarbons (CFCs) was banned the following year on Dec. 31, 1995.
There is, therefore, an urgent need for effective alternate fire extinguishing systems that do not involve HALONS. It is toward providing such a need that the present invention is directed.
Broadly, the present invention is embodied in fire suppressant compositions which are substantially free of ammonium nitrate and which comprise potassium nitrate in an amount sufficient to generate at least about 10 wt. % potassium carbonate when combusted. Most preferably, a guanidine salt, such as guanidine nitrate, is used in combination with the potassium nitrate.
These, as well as other, aspects and advantages of the present invention will become more clear from the following detailed description of the preferred exemplary embodiments thereof which follows.